Oil burner construction



1938- N. F. BENNETT OIL BURNER CONSTRUCTION Filed Feb. 18, 1935 3Sheets-Sheet 1 Nov. 8, 1938. N. F. BENNETT OIL BURNER CONSTRUCTION FiledFeb. 18, 1955 3 Sheets-Sheet 2 Cf W, K/W FY 192%.

Nov. s, 1938. N BE NETT 2,135,786

OIL BURNER CONSTRUCTION Filed Feb. 18, 1935 3 Sheets-Sheet 3 I n l enfor. fl x/1M f BEA/MSIT Patented Nov. 8, 1938 UNITED STATES PATENTOFFICE Norman Franklin Bennett, Newmarket, Ontario,

Canada Application February 18, 1935, Serial No. 7,096

9 Claims.

The principal objects of this invention are to provide a device whichwill thoroughly atomize oil used for fuel purposes including very heavyoil and effect the mixture of same with air so that the resultantmixture will ignite instantaneously with spark ignition under varyingconditions of atmosphere and temperature and will maintain a constantand uniform flame, thereby enabling the use of the device inintermittent service such as is required for house-heating equipment.

The-principal features of the invention consist in the novelconstruction and arrangement of mechanisms whereby the oil is fed to arotatable member from which it is discharged into a constricted chamberinto which air is directed under pressure by a converging annular wall,and the oil is broken into extremely fine particles and mixed withinfiowing air by an agitator member extending axially from the rotatablemember into the constricted chamber.

A further important feature of the invention consists in conducting theoil to the rotatable member through a channel surrounding the rotatablemember and applying heat thereto to pre heat the oil prior to its beingdischarged into the mixing chamber.

Referring to the drawings:

Figure 1 is a side elevation partly in section of 30 my oil burningapparatus.

Figure 2 is a plan view also partially in section and with the top coverplate removed from the casing.

Figure 3 is an enlarged sectional elevation of the oil feeding unitshowing the central shaft, the nozzle construction, the preheater andthe oil pipe leading to the oil feeding unit from the pump.

Figure 4 is a sectional view of the outer stationary nozzle showing theair pipe connecting therewith.

Figure 5 is an end elevation of the outer stationary nozzle.

Figure 6 is a sectional view of the inner rotary nozzle illustrating themulti-faced agitating 45 blade.

Figure 7 is an end elevation of the inner rotary nozzle.

Figure 8 is an enlarged longitudinal sectional view of the assemblednozzle.

Figure 9 is an enlarged longitudinal part sectional elevational view ofthe nozzle structure taken at right angles to the plane of the sectionillustrated in Figure 8.

Referring more particularly to the drawings, A indicates the device as awhole, which includes the oil feeding unit In which is generallysurrounded by the casing ll supported from the framework of other partsof the apparatus. This includes the driving motor l2, the fan i3, aircompressor H and oil pump I5. The arrangement of various elements could,of course, be modified should this be desired but the disclosure madeparticularly in Figures 1 and 2 illustrates a very compact and efficientunit.

One of the salient features of my invention 5 resides in theconstruction and arrangement of the oil feeding unit including theattached nozzle construction, the oil feeding unit being in the form ofa tubular member which is preferably connected at one end of the pumpcasing l5 and carries, on its opposite end a stationary nozzle l6.Within the oil feeding unit I0 is a shaft I! which is placed in drivingconnection with the shaft l8 the latter being driven by the motor, andoperating the fan, compressor and pump, so'that shaft I! is constantlyrotated during the operation of the motor. The relation between the oilfeeding unit 10 and the shaft i1 is such that between them, there isprovided a space or clear passageway I 8 for supplying the oil to thenozzle, the construction preferably being such that the shaft is reducedin diameter intermediately of its length so as to provide the space IS,the larger ends of the shafts 2|! and 2| forming bearings.

Through the outer end of the shaft I! extending up to and through theenlarged portion 2| is a bore 22 which'is intersected by the transversepassage or passages 23 that communicate with the space I! so that oilmay be fed through this latter space, through the transverse passages 23into the bore 22, from whence it is elected to be discharged from thenozzle IS.

The reduced portion of the shaft I1 is preferably formed with screwthreading or the like 23' so that as the shaft constantly rotates duringthe operation of the apparatus, the oil, regardless of the fact that itmay be very sluggish due to cold weather, will always be positivelypassed through the channel or space i9 surrounding this shaft and, whilethe pressure set up by the pump usually would be sufficient to providefor the ejection of the oil from the burner nozzle, it is apparent thatwhen the oil is sluggish and will not so read'ly'respond to the pressureof the pump this rotating shaft formed with screw threading or the likewill constitute a positive agitator and provide for a steady ejection ofoil.

The rotating shaft also serves a very important function in providingfor the breaking up of the oil into a finely atomized spray, which istaken care of by various expedients. In this connection the end of theshaft is provided with a nipple 24 or other suitable means for receivinga rotary nozzle 25 which is rigidly secured on the end of the shaft indriving engagement therewith so that when the shaft rotates the nozzledoes likewise. The nozzle 25 is formed with a chamber 26 whichcommunicates with the bore 22 of the shaft, the other end of the nozzlebeing formed preferably with a pair of discharge openings 21 00 betweenwhich, and projecting from the end of the nozzle, is an agitating memberin the form of a blade 2| presenting a plurality of longitudinal faceswhich engage the streams of oil projected from the openings 21, thusbreaking up the streams and throwing the oil outwardly against the wallof the nozzle It. This blade is disposed between the orifices 21 whichare positioned above and below opposite faces of the agitator.

As shown, the rotary nozzle 28 is spaced from the stationary nozzle it,the blade or agitator 28 projecting from nozzle 28 into the spacebetween said nozzles. The stationary nozzle ii is provided with adischarge opening which is designed to register with the dischargeopenings 21 in nozzle 28 and the blade or agitator 28 is preferablytapered to a point or substantially so. as clearly illustrated in Figure6 and Figures 8 and 9, so that it may project partially into thedischarge opening 20 of the agitator and thus provide for a violentagitation of the oil as it passes between the discharge openings 21 ofthe rotary nozzle 25 and discharge opening 29 of stationary nozzle Ii.

The nomle I l is tapered and particularly its inner surface, as at 30,the inner or rotary nozzle 28 having a portion tapered as at II, or inother words its end is frustro-conical so that the space between thnozzles finally takes the form of a conical passageway converging at apoint adjacent to the discharge opening 20 of the nozzle and theagitator 28. As shown in Figure 4-and Figures 8 and 9, the stationarynozzle It is provided with an opening 32 to receive the conduit 22 whichis designed to supply compressed air to the space between the nozzles sothat in combination with the violent agitation of the oil by theagitating blade 2|, a blast of compressed air converges on the blade anddischarge opening 2! whereby the oil will be broken up into an extremelyfine spray.

The stationary nozzle I6 is provided with a slot ll intersecting thedischarge opening 20 (see particularly Figures 4, 5, 8, and 9) so thatthe spray of atomized oil and air being discharged from the stationarynozzle may spread within the fire box.

Prior to passing to the rotary nozzle 2!, the oil is partially broken upthrough the type of construction employed. For instance, as the oilpasses from the passageway I! in the oil feeding unit to the bore 22 ofthe shaft ll,itenters the passageways 22 which constantly rotate withthe shaft and therefore the oil entering these passageways will beagitated and broken up and particularly so in view of the fact that theoil enters these passageways against the action of centrifugal force.Moreover, when the oil is free flowing and under considerable pressure,it will be forced against the threading on shaft I! which will tend tocause a breaking up of the fluid. In view of these facts, therefore, theoil, when it is discharged with the compressed air at the end of thenozzle, is broken up to such an extent that it will immediately igniteby means of a spark ignition. This is an extremely important point inview of the fact that great difficulties have been experienced inproviding for an instantaneous ignition of an oil spray by sparkignition and when it is considered that this can be effected regardlessof the type of fuel oil used, the full importance of the developmentwill be realized. Moreover, the

ignition device can be positioned directly in advance and in the path ofthe spray, as will be referred to hereinafter.

An important feature in the construction of the oil feeding unit is thearrangement by which the oil may be instantaneously preheated whilebeing supplied to the nozzle and agitated, which is a factor ininstantaneous ignition. For instance, by flowing the oil through thepassageway l9 surrounding the shaft, a comparatively large volume of oilpasses through the oil feeding unit, but by reason of the fact that thepassageway I9 is restricted in depth as between the interior wall of theoil feeding unit and the exterior surface of the shaft, a body of oilhaving a large surface area and limited-depth flows through the oilfeeding unit and therefore, by completely surrounding the surface of theoil feeding unit with an electric preheater 25 directly overlying theoil channel, the oil passing through this channel can be instantaneouslyheated. In other words a thin body of oil is directly heated withoutsacrificing volume, the oil feeding unit shell being preferably of brassor like metal which heats rapidly.

The preheater shown is provided with clamps or the like 36 to which thecircuit wires may be attached and a movable clamp 21 is provided whichmay be moved along the preheater 'so that the amount of resistance wirethrough which the current passes can be changed to vary the amount ofheat desired. The preheater is operated on the general circuit employedfor the driving motor, the circuit being of well known characterincluding thermostat control and a relay and switch for generalautomatic control. In the present case the connections are such that thepreheater is cut in to operate just prior to the operation of the motorand the motor is automatically put into operation a few seconds later.

The casing ll surrounding the oil feeding unit may be formed with aspider or other suitable support 39 through which the nozzle I6 mayproject. The spider or other device employed acts as a general supportand may serve as a suitable mounting for the insulating bushings 40 ofthe ignition electrodes I. These latter are curved at their outer endsand spaced apart to provide a suitable spark gap and are positioned wellin advance of the nozzle l6 and directly in the path of the atomized oilbeing discharged from the nozzle so that under the conditions broughtabout by the apparatus, the spark ignition will bring aboutinstantaneous combustion.

The inner ends of the ignition electrodes are provided with suitableclamping connections such as 42 to receive the circuit wires which arealso connected in the general circuit for operating the motor andarranged in usual manner so that ignition takes place immediately thatthe motor starts and after combustion is established the ignitioncircuit is cut out. The general circuit employed for this is of wellknown character.

The casing l I may be provided with a removable cover plate 43 and isprovided with an opening 44 regulated by a suitable slide damper or thelike 45, the opening 44 being designed for connection with the conduit46 of the fan I! so that air for supporting proper combustion may bedelivered through the gun casing into the fire box.

It will be noted that the motor, fan and compressor are all driven froma single shaft, the compressor being simply secured to the fan casing bymeans of a suitable mounting ring or the like 41 so that a very compactunit is provided with provision for the driving of the shaft II in avery simple manner. The compressor is of ordinary form and through thecompressed air supply line 33 which extends between the compressor andthe nozzle l6, compressed air is consuch as one in the nature of asleeve having an.

opening through which the oil may discharge, the sleeve being rotatableto control the size of, or to shut off the opening.

A particular feature which is notable is the very short oil deliveryline 52 which eliminates possibility of clogging, as is often the casewhere it is necessary to employ long oil supply lines. The oil issupplied to the pump from an auxiliary oil tank 53 which receives itssupply from the main tank.

It is apparent therefore, that when the apparatus is in operation oilwill be supplied at a constant desired pressure to the oil feeding unit,the oil being instantaneously preheated, then broken up finely throughviolent agitation resulting from the operation of the auxiliaryagitating means, the multifaced agitating member 28 and the convergingblast of air from all sides which is directed by the shape of the innerand outer nozzles. It is thus discharged in a fine atomized spray fromthe end of nozzle l6, whereupon ignition takes place and a very hotflame is produced.

In practice this burner has proved efficient when using various gradesand types of oil as fuel, as well as used motor oil and due to thearrangement and construction of the parts described, it has performedefliciently with instantaneous ignition after a few seconds preliminarypreheating, this favourable performance being due to the facility withwhich the oil may be heated, the manner in which even sluggish oil ispositively fed, and the arrangement for constantly breaking up the oilinto a very fine atomized condition. The preferred construction has, ofcourse, been shown, but this may be modified to some extent whilemaintaining the principles employed.

What I claim as my invention is:-

1. An oil burner comprising a stationary nozzle converging to adischarge opening, a rotary nozzle arranged coaxial with said stationarynozzle and discharging oil longitudinally in the direction of thedischarge of the stationary nozzle, a paddle-like agitating memberextending longitudinally from the end of said rotary nozzle into theconvergent discharge end of the stationary nozzle and rotating with saidrotary nozzle to engage and break up the oil being discharged from saidrotary nozzle, means for feeding oil to said rotary nozzle, and meansfor directing a blast of air through said stationary, nczzle around saidrotary nozzle,

2. An oil burner comprising a stationary nozzle converging to acylindrical orifice, a rotary nozzle arranged co-axial with saidstationary nozzle having openings in the end thereof discharging streamsof oil in a longitudinal direction into said cylindrical orifice, anagitating member projecting from the end of said rotary nozzle andarranged between the oil discharge openings and having a plurality oflongitudinal faces adapted to engage and break up the streams of oil,said agitating member extending into the cylindrical discharge orificeof the stationary nozzle and having its longitudinal edges rotating inclose proximity to the cylindrical wall, means for feeding oil into saidrotary nozzle, and means for di recting a blast of air through saidstationary nozzle around said rotary nozzle.

3. An oil burner as claimed in claim 2 in which the agitating member isin the form of a flat blade arranged co-axially of said rotating nozzleand between the oil discharge openings, the flat faces of said blade inrotation beating the lagging oil streams and throwing the oil againstthe surrounding wall of the stationary nozzle to be mixed with the flowof air through said stationary nozzle.

4. An oil burner as claimed in claim 1 in which the rotary nozzle isprovided with a hollow chamber adjacent to the end and communicatingwith the discharge openings, said discharge openings being substantiallyparallel with the axis of said nozzle.

5. An oil burner comprising a stationary tubular member, a nozzlemounted on the end of said tubular member converging to a cylindricaldischarge opening, a shaft rotatably mounted axially within said tubularmember and spaced from the inner wall thereof, said shaft having acentral bore and passages connecting said bore with the annular spacebetween the shaft and tube, a nozzle secured to the end of said shafthaving a chamber therein, communicating with said bore and havingopenings through the outward end thereof adapted to project thin streamsof oil into the cylindrical discharge opening of the stationary nozzle,8. blade extending from the end of said nozzle mounted on said shaft andprojecting into the discharge opening of the stationary nozzle to breakup the oil flowing through said openings arranged either side of saidblade, means for feeding oil through said tubular member and into andthrough said rotary nozzle, and means for feeding a blast of air throughsaid stationary nozzle around the discharge end of the rotary nozzle.

6. An oil burner as claimed in claim 5 in which the shaft is supportedin a bearing closing the outer end of the tubular member which separatesthe annular oil passage within the tubular member from the annular airchamber within the nozzle mounted on the end thereof.

7. An oil burner as claimed in claim 5 in which the portion of the shaftspaced from the enclosing tube is threaded externally to assist thedelivery of an annular body of oil to the nozzle.

8. An oil burner as claimed in claim 5 in which the tubular member isthreaded externally at its end and the stationary nozzle is internallythreaded and adjustably mounted on the threaded end of the tube topermit an adjustment of the spacing between the discharge endof therotary nozzle and the inner wall of thedischarge end of the stationarynozzle to regulate the flow of air.

9. An oil burner as claimed in claim 1 in which the converging,stationary nozzle is of frusto conical form and the discharge opening isan axially arranged cylindrical passage, and the rotary nozzle is offrusto-conica1 form having its tapering exterior wall substantiallyparallel with the tapering interior wall of the stationary nozzle, andhaving the discharge openings in the small end thereof arranged eitherside of the axis of the burner and projecting streams of oil either sideof the agitating member and into the cylindrical discharge opening ofthe stationary nozzle.

NORMAN FRANKLIN BENNETT.

